1. Field of the Invention
The present invention relates generally to an ice making machine and more particularly to the type of ice making machine which includes an ice forming plate formed with a plurality of protrusions laterally spaced from one another and extending vertically in the direction along which icing water (i.e. water to be frozen to ice) flows.
2. Description of the Prior Art
In an ice making machine of the type mentioned above, a pair of vertically extending ice forming plates 1 are generally disposed in opposition to each other with an evaporator 2 being interposed therebetween, as is shown in FIGS. 3 and 4 of the accompanying drawings. During the ice making or forming operation, a coolant is forced to flow through the evaporator 2 while the icing water to be frozen to ice is fed from a icing water distributor (not shown) disposed above the ice forming plates 1 and flows downwardly along the surfaces thereo between vertical protrusions 3, whereby ice pellets 6 are formed on the surfaces of the ice forming plates 1. When the ice pellets 6 thus formed have grown to a predetermined size, as detected by appropriate known detecting means, the ice making machine is changed over to an ice removing or deicing operation. During the deicing operation, a hot gas is supplied to flow through the evaporator 2 while deicing water is sprayed over the rear or inner surfaces of the ice forming plates 1 from spray nozzle orifices 5 formed in a water distributor 9. Consequently, those portions of the ice pellets 6 which are in contact with the outer surfaces of the ice forming plates 1 melt due to the heat and the pellets 6 fall into an ice storage box (not shown).
The ice forming plates 1 are secured at both lateral ends 7 thereof to brackets 4, respectively. As a result, grooves 10 having a V-shaped cross-section are formed between the bracket 4 and the ice forming plates 1, as shown in FIG. 4. Accordingly, as will be readily understood by those skilled in the art, the icing water flowing downwardly over the surface of ice being formed on the leftmost region is likely to migrate beyond the leftmost protrusion 3 (as viewed in FIG. 4) into the grooves 10 as the ice pellets 6 grow during the course of the ice making operation, whereby ice 8 is also formed in the grooves 10.
During the ice removing operation, deicing water is sprayed over the ice forming plates. It is however noted that the deicing water is fed to the rear or inner surfaces rather than the outer surfaces of the ice forming plates, and flows downwardly at middle portions of the regions defined between the protrusions 3. Consequently, little heat is transmitted from the deicing water to the portions of the ice forming plates which define the grooves 10. As a result, the ice 8 will remain unremoved even after the deicing cycle. Accordingly, upon the start of a succeeding ice making operation, the ice 8 remaining within the groove 10 will further grow to such an extent that the ice 8 is joined to the adjacent ice 6. Thus, in the succeeding deicing operation, not only ice 8 but also the ice pellets 6 in the leftmost rows located adjacent to the grooves 10 tend to remain on the ice forming plates 1. Even if the ice 8 and/or ice pellets 6 of the leftmost row (as viewed in FIG. 4) joined thereto could be released from the ice forming plates during the deicing operation, ice pellets having an undesirable shape will then be stored within the ice storage box.
Additionally, when the ice grows within the V-shape groove 10, the bracket 4 and the leftmost protrusion 3 tend to be separated from each other, causing deformation of the ice forming plates 1. This results in the ice forming plates becoming detached fro the evaporator 2, which in turn means that the ice making capability of the machine is drastically lowered and the removal of the ice pellets becomes practically impossible in extreme cases.
It is further noted that when the ice remains on the ice forming plates at the beginning of the ice making operation, the load for refrigeration is small, resulting in an increase in the amount of liquid phase coolant recirculated back to the compressor, which then has to bear a correspondingly increased load. This means that the compressor is more likely to fail.